Signaling accommodation

• US 6,876,248 B2
• Filed: 05/28/2002
• Issued: 04/05/2005
• Est. Priority Date: 02/14/2002
• Status: Expired due to Fees

• Current Assignee: Rambus Inc.
• Original Assignee: Rambus Inc.
• Inventors: Nguyen, Huy M., Lau, Benedict C.
• Primary Examiner(s): Cunningham, Terry D.
• Assistant Examiner(s): TRA, ANH QUAN
• Application Number:
  US10/157,593
• Publication Number:
  US 20030151450A1
• Time in Patent Office: 1,043 Days
• Field of Search: 327/538, 327/543, 327/541, 327/307, 327/540, 323/280, 323/281
• US Class Current: 327/538
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C

Abstract

A receiving unit may implement voltage compensation using a parameters table, an analog calibration component, and/or a digital calibration component. In certain implementation(s), an integrated circuit may include a voltage driver that modifies a supplied compensated voltage based on a feedback signal. The feedback signal may be produced responsive to a distributed voltage version of the compensated voltage, to a received data signal, and to a comparison involving an expected data value. In other implementation(s), a parameters table may be initialized by storing calibration values in entries in association with respective multiple identifications of multiple external points. In still other implementation(s), a particular calibration value of multiple calibration values may be ascertained, with the particular calibration value associated with a particular external point; the particular calibration value may be activated; and data from the particular external point may be received using the particular calibration value. Other implementations are also described.

Claims

1. A receiving unit that receives one or more data signals, the one or more data signals having common mode voltage at the receiving unit, the receiving unit comprising:

a voltage driver that supplies a compensated voltage in response to a feedback signal;

wherein the compensated voltage is distributed to produce a distributed voltage; and

a feedback unit that is responsive to the distributed voltage and to at least one data signal of the one or more data signals;

wherein the feedback unit controls the feedback signal to establish the distributed voltage at a value that is approximately equal to the common mode

voltage of the at least one data signal of the one or more data signals; and

wherein the feedback unit is inactive and is not receiving the at least one data signal of the one or more data signals during an operational phase of the receiving unit.

2. A receiving unit, comprising:

a voltage driver that supplies a compensated voltage and modifies the compensated voltage based on a feedback signal;

a feedback unit that produces the feedback signal, wherein the feedback unit produces the feedback signal responsive to a comparison involving an expected data value, and the feedback unit receives as inputs a distributed voltage and a data signal; and

a data structure having a plurality of entries, each entry of the plurality of entries configured to store an identification and an associated attribute for a transmitting unit corresponding to the identification;

wherein a change to the compensated voltage results in a change in the distributed voltage.

3. The receiving unit as recited in claim 2, wherein the associated attribute comprises a voltage compensation value;

and wherein the voltage driver is configured to utilize the voltage compensation value when receiving a data signal from the transmitting unit that corresponds to the identification.

4. The receiving unit as recited in claim 3, wherein the voltage driver is further configured to utilize the voltage compensation value when modifying the compensated voltage based on the feedback signal.

5. A receiving unit, comprising:

a voltage driver that supplies a compensated voltage using a variable gain amplifier, wherein the voltage driver modifies the compensated voltage based on a feedback signal that adjusts a gain of the variable gain amplifier; and

a feedback unit that produces the feedback signal, wherein the feedback unit produces the feedback signal responsive to a comparison involving an expected data value, and the feedback unit receives as inputs a distributed voltage and a data signal;

wherein a change to the compensated voltage results in a change in the distributed voltage;

wherein the feedback unit includes at least one signal receiver and at least one calibration component; and

wherein the at least one signal receiver receives as inputs the distributed voltage and the data signal and produces an output based on a comparison between the distributed voltage and the data signal; and

wherein the at least one calibration component comprises a digital calibration component, the digital calibration component configured to receive the output of the at least one signal receiver and to produce the feedback signal.

6. A receiving unit, comprising:

a voltage driver that supplies a compensated voltage and modifies the compensated voltage based on a feedback signal; and

a feedback unit that produces the feedback signal, wherein the feedback unit produces the feedback signal responsive to a comparison involving an expected data value, and the feedback unit receives as inputs a distributed voltage and a data signal;

wherein a change to the compensated voltage results in a change in the distributed voltage;

wherein the feedback unit includes at least one signal receiver and at least one calibration component; and

wherein the at least one signal receiver receives as inputs the distributed voltage and the data signal and produces an output based on a comparison between the distributed voltage and the data signal; and

wherein the at least one calibration component comprises a digital calibration component, the digital calibration component configured to receive the output of the at least one signal receiver and to produce the feedback signal responsive to a comparison of the output to the expected data value.

7. A receiving unit, comprising:

a voltage driver that supplies a compensated voltage using a variable gain amplifier, wherein the voltage driver modifies the compensated voltage based on a feedback signal that adjusts a gain of the variable gain amplifier; and

a feedback unit that produces the feedback signal, wherein the feedback unit produces the feedback signal responsive to a comparison involving an expected data value, and the feedback unit receives as inputs a distributed voltage and a data signal;

wherein a change to the compensated voltage results in a change in the distributed voltage;

wherein the feedback unit includes at least one signal receiver and at least one calibration component; and

wherein the at least one signal receiver receives as inputs the distributed voltage and the data signal and produces an output based on a comparison between the distributed voltage and the data signal;

wherein the at least one calibration component comprises a digital calibration component, the digital calibration is component configured to receive the output of the at least one signal receiver and to produce the feedback signal responsive to a comparison of the output to the expected data value; and

wherein the feedback signal is produced so as to cause the voltage driver to increase the compensated voltage until a high voltage extreme is determined by detecting a data error as a result of the comparison of the output to the expected data value.

8. A receiving unit, comprising:

a voltage driver that supplies a compensated voltage using a variable gain amplifier, wherein the voltage driver modifies the compensated voltage based on a feedback signal that adjusts a gain of the variable gain amplifier; and

a feedback unit that produces the feedback signal, wherein the feedback unit produces the feedback signal responsive to a comparison involving an expected data value, and the feedback unit receives as inputs a distributed voltage and a data signal;

wherein a change to the compensated voltage results in a change in the distributed voltage;

wherein the feedback unit includes at least one signal receiver and at least one calibration component; and

wherein the at least one signal receiver receives as inputs the distributed voltage and the data signal and produces an output based on a comparison between the distributed voltage and the data signal;

wherein the at least one calibration component comprises a digital calibration component, the digital calibrationcomponent configured to receive the output of the at least one signal receiver and to produce the feedback signal responsive to a comparison of the output to the expected data value; and

wherein the feedback signal is produced so as to cause the voltage driver to decrease the compensated voltage until a low voltage extreme is determined by detecting a data error as a result of the comparison of the output to the expected data value.

9. A system having voltage compensation, comprising:

at least one signal receiver, wherein the at least one signal receiver has a first input that receives a first voltage and a second input that receives a second voltage, the second voltage corresponding to a received data signal; and

a voltage driver, wherein the voltage driver supplies the first voltage to the first input of the at least one signal receiver, the voltage driver configured to change the first voltage supplied to the at least one signal receiver responsive to an output of the at least one signal receiver;

wherein the system has an operational phase and a calibration phase, the voltage driver capable of changing the first voltage supplied to the at least one signal receiver responsive to the output of the at least one signal receiver during the calibration phase but not during the operational phase.

10. The system as recited in claim 9, wherein the first voltage supplied to the first input of the at least one signal receiver is a degraded version of an output voltage of the voltage driver.

11. The system as recited in claim 9, wherein the first voltage supplied to the first input of the at least one signal receiver is changed to be approximately equal to a common mode voltage of the received data signal by the voltage driver.

12. The system as recited in claim 9, wherein the second voltage comprises at least one of (i) a data voltage of the received data signal and (ii) a common mode voltage of the received data signal.

13. An electronic arrangement, comprising:

a voltage driver means for supplying a compensated voltage, the voltage driver means adapted to modify the compensated voltage based on a feedback signal; and

a feedback means for producing the feedback signal, wherein the feedback means produces the feedback signal responsive to a comparison involving an expected data value, and the feedback means receives as inputs a distributed voltage and a data signal;

wherein a change to the compensated voltage results in a change in the distributed voltage; and

wherein the feedback means includes a signal comparison means that compares the distributed voltage to the data signal to produce a comparison output; and

wherein the feedback means further includes digital calibration means for comparing the expected data value to the comparison output to produce the feedback signal at least partially responsive thereto.

14. A memory system, comprising:

a plurality of memory storage cells;

a voltage driver that supplies a compensated voltage, wherein the voltage driver modifies the compensated voltage based on a feedback signal;

a plurality of signal receivers, the plurality of signal receivers adapted for receiving a data signal capable of storage within the plurality of memory storage cells, wherein the plurality of signal receivers receive at least a version of the compensated voltage; and

a feedback unit that produces the feedback signal, the feedback unit including a signal receiver of the plurality of signal receivers, the feedback unit configured to produce the feedback signal using the data signal received via the signal receiver and responsive to a comparison involving an expected data value.

15. The memory system as recited in claim 14, further comprising:

a parameters table, the parameters table including a plurality of entries, each entry of the plurality of entries capable of storing an identification and an associated voltage compensation value, each identification corresponding to a potential transmitting unit;

wherein the voltage driver is configured to utilize the associated voltage compensation value to modify the compensated voltage when the signal receiver of the feedback unit is receiving the data signal from the potential transmitting unit that corresponds to the identification.

16. The memory system as recited in claim 15, wherein the memory system comprises a memory controller;

and wherein the plurality of memory storage cells comprise a buffer.

17. The memory system as recited in claim 14, further comprising:

an identification;

wherein the identification enables a master to access the plurality of memory storage cells.

18. The memory system as recited in claim 17, wherein the memory system comprises a memory storage module;

and wherein the plurality of memory storage cells comprise a memory storage array.

19. The memory system as recited in claim 14, further comprising:

a bus, wherein the bus is in communication with the plurality of signal receivers and is capable of propagating the data signal.

20. A method for providing a compensated voltage when receiving signals, comprising:

supplying a voltage;

receiving a data signal from an external point;

producing a feedback signal responsive to the data signal, the voltage, and an expected data value;

modifying the voltage being supplied in the action of supplying a voltage based, at least partly, on the feedback signal;

sending a data value to the external point; and

instructing the external point to return the data value;

wherein the action of receiving occurs after the actions of sending and instructing, and wherein the data signal includes the data value.

22. The method as recited in claim 20, wherein the action of modifying comprises the actions of:

increasing the voltage if a common mode voltage of the data signal is greater than a version of the voltage; and

decreasing the voltage if a common mode voltage of the data signal is less than a version of the voltage.

21. A method for providing a compensated voltage when receiving signals, comprising:

supplying a voltage;

receiving a data signal from an external point;

producing a feedback signal responsive to the data signal, the voltage, and an expected data value; and

modifying the voltage being supplied in the action of supplying a voltage based, at least partly, on the feedback signal;

wherein the action of producing comprises the actions of;

determining a common mode voltage of the data signal, the common mode voltage of the data signal potentially reflective of the expected data value; and

comparing the common mode voltage of the data signal to a version of the voltage to produce the feedback signal.

23. A method for providing a compensated voltage when receiving signals, comprising:

supplying a voltage;

receiving a data signal from an external point;

producing a feedback signal responsive to the data signal, the voltage, and an expected data value; and

modifying the voltage being supplied in the action of supplying a voltage based, at least partly, on the feedback signal;

wherein the action of producing comprises the actions of;

comparing the data signal to a version of the voltage to produce a preliminary feedback signal;

comparing the preliminary feedback signal to the expected data value to determine whether or not a data receiving error has occurred; and

producing the feedback signal responsive to determining whether or not a data receiving error has occurred.

24. A method for voltage compensation, comprising:

sampling data at a sampler to produce an average value of the data;

receiving the average value of the data as a first input of a signal receiver;

receiving a distributed voltage as a second input of the signal receiver;

comparing the average value of the data to the distributed voltage at the signal receiver to determine an output therefrom;

changing the distributed voltage responsive to the output;

receiving additional data as the first input of the signal receiver;

comparing the additional data to the changed distributed voltage at the signal receiver to determine an additional output therefrom; and

storing the additional output in at least one memory storage cell.

25. The method as recited in claim 24, further comprising:

transmitting the data to a destination;

instructing the destination to transmit the data from the destination so that the data can be sampled in the action of sampling data at a sampler.

26. The method as recited in claim 24, wherein the action of sampling data at a sampler comprises at least one of the following actions:

low pass filtering the data at a low pass filter; and

integrating the data at an integrator.

27. The method as recited in claim 24, wherein the data comprises a data pattern having a duty cycle of approximately fifty percent (50%).

28. The method as recited in claim 27, wherein the data pattern is selected from the group comprising 01010101, 00110011, 00010111, 10101010, 11001100, and 10101001.

29. A method for voltage compensation, comprising:

sampling data at a sampler to produce an average value of the data;

receiving the average value of the data as a first input of a signal receiver;

receiving a distributed voltage as a second input of the signal receiver;

comparing the average value of the data to the distributed voltage at the signal receiver to determine an output therefrom; and

changing the distributed voltage responsive to the output;

wherein the action of changing the distributed voltage responsive to the output comprises;

changing a value of an up/down counter responsive to the output;

applying the value of the up/down counter to establish a gain of a variable gain voltage amplifier; and

amplifying a nominal voltage with the variable gain voltage amplifier to produce a compensated voltage;

wherein a change to the distributed voltage results from the action of amplifying a nominal voltage with the variable gain voltage amplifier to produce a compensated voltage.

30. A method for voltage compensation, comprising:

sampling data at a sampler to produce an average value of the data;

receiving the average value of the data as a first input of a signal receiver;

receiving a distributed voltage as a second input of the signal receiver;

comparing the average value of the data to the distributed voltage at the signal receiver to determine an output therefrom; and

changing the distributed voltage responsive to the output;

wherein the action of changing the distributed voltage responsive to the output comprises;

changing a value of an up/down counter responsive to the output;

loading a register with the value of the up/down counter;

providing the value from the register to a variable gain voltage amplifier to establish a gain thereof; and

amplifying a nominal voltage with the variable gain voltage amplifier to produce a compensated voltage;

wherein a change to the distributed voltage results from the action of amplifying a nominal voltage with the variable gain voltage amplifier to produce a compensated voltage.

31. An integrated circuit, comprising:

a voltage driver that supplies a compensated voltage, wherein the voltage driver modifies the compensated voltage based on a feedback signal;

a calibration component that receives a data signal, wherein the calibration component includes a sampler, and the sampler is adapted to receive the data signal and to produce a common mode voltage of the data signal; and

a signal receiver that compares a first input to a second input and outputs the feedback signal, wherein the signal receiver receives a distributed voltage at the first input and the common mode voltage of the data signal at the second input;

wherein the distributed voltage comprises a degraded version of the compensated voltage; and

wherein the calibration component comprises a pre-charging component, and the pre-charging component is adapted to pre-charge the sampler prior to an initialization phase.

32. An integrated circuit, comprising:

a voltage driver that supplies a compensated voltage, wherein the voltage driver modifies the compensated voltage based on a feedback signal using a variable gain of the voltage driver;

a calibration component that receives a data signal, wherein the calibration component includes a sampler, and the sampler is adapted to receive the data signal and to produce a common mode voltage of the data signal; and

a signal receiver that compares a first input to a second input and outputs the feedback signal, wherein the signal receiver receives a distributed voltage at the first input and the common mode voltage of the data signal at the second input;

wherein the distributed voltage comprises a degraded version of the compensated voltage;

wherein the variable gain of the voltage driver changes based on the feedback signal such that the compensated voltage is increased when the distributed voltage is lower than the common mode voltage of the data signal and decreased when the distributed voltage is greater than the common mode voltage of the data signal; and

wherein the variable gain of the voltage driver changes as an up/down counter is changed based on the feedback signal.

33. An integrated circuit, comprising:

a voltage driver that supplies a compensated voltage, wherein the voltage driver modifies the compensated voltage based on a feedback signal using a variable gain of the voltage driver;

a calibration component that receives a data signal, wherein the calibration component includes a sampler, and the sampler is adapted to receive the data signal and to produce a common mode voltage of the data signal; and

a signal receiver that compares a first input to a second input and outputs the feedback signal, wherein the signal receiver receives a distributed voltage at the first input and the common mode voltage of the data signal at the second input;

wherein the distributed voltage comprises a degraded version of the compensated voltage;

wherein the variable gain of the voltage driver changes based on the feedback signal such that the compensated voltage is increased when the distributed voltage is lower than the common mode voltage of the data signal and decreased when the distributed voltage is greater than the common mode voltage of the data signal; and

wherein the variable gain of the voltage driver is determined by a digital value stored in a register.

34. A system having voltage compensation, comprising:

sampling means for sampling a received data signal to produce an average value of the received data signal;

receiving means for receiving the average value of the received data signal as a first input and a distributed voltage as a second input and for comparing the average value of the received data signal to the distributed voltage to determine a comparison output;

voltage means for modifying a compensated voltage responsive to the comparison output; and

degrading means for degrading the compensated voltage to the distributed voltage;

wherein the sampling means is active during a calibration phase of the system and inactive during an operational phase of the system.

35. A method for voltage compensation, comprising:

receiving data as a first input of a signal receiver;

receiving a distributed voltage as a second input of the signal receiver;

comparing the data to the distributed voltage at the signal receiver to determine at least one result therefrom;

determining whether there is a difference between the at least one result and an expected value;

if there is a difference, noting a current value of a register as an extreme value; and

if there is not a difference, altering the current value of the register; and

changing a compensated voltage responsive to the current value of the register;

wherein a change to the compensated voltage results in a change in the distributed voltage.

36. The method as recited in claim 35, wherein the at least one result and the expected value each comprise an eight (8)-bit data pattern.

37. The method as recited in claim 35, wherein the action of noting a current value of a register as an extreme value comprises the action of storing the current value of the register into at least one of a high voltage point register and a low voltage point register.

38. The method as recited in claim 35, wherein the action of altering the current value of the register comprises at least one of the following actions:

incrementing the current value of the register, decrementing the current value of the register, and setting the current value of the register to a new value.

39. The method as recited in claim 35, further comprising:

determining whether a high extreme value and a low extreme value have been noted;

if so, determining an intermediate value between the high extreme value and the low extreme value; and

setting the current value of the register to equal the intermediate value.

40. The method as recited in claim 39, wherein the action of determining an intermediate value between the high extreme value and the low extreme value comprises at least one of the following actions:

determining an intermediate value using a median value between the high extreme value and the low extreme value; and

determining an intermediate value using a median value between the high extreme value and the low extreme value and an offset therefrom.

41. A receiving unit, comprising:

a voltage driver that supplies a compensated voltage, wherein the voltage driver modifies the compensated voltage based on a feedback signal;

a signal receiver that compares a first input to a second input and outputs a result, wherein the signal receiver receives a distributed voltage at the first input and a data signal at the second input; and

a calibration component that receives the result and produces the feedback signal;

wherein the calibration component includes a comparison unit and calibration data;

wherein the comparison unit is configured to receive the result and the calibration data, to compare the result to the calibration data, and to determine whether the result differs from the calibration data;

wherein the distributed voltage comprises a degraded version of the compensated voltage.

42. The receiving unit as recited in claim 41, wherein the feedback signal is formed responsive to the determination by the comparison unit of whether the result differs from the calibration data.

43. The receiving unit as recited in claim 41, wherein the feedback signal is formed responsive to the determination by the comparison unit of whether the result differs from the calibration data such that the voltage driver modifies the compensated voltage when the result does not differ from the calibration data.

44. The receiving unit as recited in claim 41, further comprising:

control logic that includes a high voltage point register and a low voltage point register, wherein the control logic is configured to provide the feedback signal such that the voltage driver modifies the compensated voltage when the result does not differ from the calibration data, and wherein the control logic is further configured to store a register value into at least one of the high voltage point register and the low voltage point register when the result does differ from the calibration data.

45. The receiving unit recited receiving as in claim 41, further comprising:

control logic that includes a high voltage point register and a low voltage point register;

wherein the control logic is configured to provide the feedback signal such that the voltage driver modifies the compensated voltage when the result does not differ from the calibration data;

wherein the control logic is further configured to store a register value into at least one of the high voltage point register and the low voltage point register when the result does differ from the calibration data; and

wherein the control logic is adapted to determine an intermediate voltage point value based on the high voltage point register and the low voltage point register and to provide the intermediate voltage point value to the voltage driver.

46. The receiving unit as recited in claim 41, wherein the voltage driver includes a storage register that controls a gain of the voltage driver;

and

further comprising;

control logic that includes a high voltage point register and a low voltage point register;

wherein the control logic is configured to provide the feedback signal at least indirectly to the storage register such that the voltage driver modifies the compensated voltage when the result does not differ from the calibration data;

wherein the control logic is further configured to store a register value from the storage register of the voltage driver into at least one of the high voltage point register and the low voltage point register when the result does differ from the calibration data; and

wherein the control logic is adapted to determine an intermediate voltage point value based on the high voltage point register and the low voltage point register and to provide the intermediate voltage point value to the storage register of the voltage driver.